PLC safety monitoring and dynamic measurement method and system

A measurement method and measurement system technology, applied in the field of PLC security real-time monitoring and measurement, can solve the problems of lack of protection, CPU is easy to be attacked at the same time, and cannot be detected, so as to strengthen security protection, prevent PLC security problems, The effect of high security

Active Publication Date: 2020-03-31
ZHENGZHOU XINDA JIEAN INFORMATION TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

On the one hand, this method has two or more CPUs that are easy to be attacked at the same time, so it cannot effectively monitor and protect against malicious codes changing the PLC control logic. On the other hand, it cannot detect a

Method used

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  • PLC safety monitoring and dynamic measurement method and system

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034]This embodiment provides a PLC security real-time monitoring and measurement method, such as figure 1 As shown, the method includes the following steps:

[0035] Preparation Phase

[0036] S1. Analyzing the application program of PLC, determining one or more operation key points in the operation process of the application program, and determining the PLC scan cycle interval corresponding to the operation key points;

[0037] S2. In the normal operation state of the PLC, according to the PLC scan cycle interval corresponding to the key point of operation, in each PLC scan cycle corresponding to the key point of operation, record the PLC input, output, and output of the scan cycle respectively. And the value of each internal soft component state, and encode according to the predetermined rules to obtain the state code word;

[0038] S3. In the normal operation state of the PLC, change the values ​​of the various inputs of the PLC, so that the recorded values ​​of the var...

Embodiment 2

[0053] The difference between this embodiment and Embodiment 1 is that another method for encoding according to predetermined rules described in step S2 and step S4 is provided, including: inputting, outputting, and The value of each soft component state inside the PLC is written in binary form according to the predetermined rules, and placed in the predetermined binary code position, combined to form a binary code word, after adding a check code in the binary code word, as a code The following status codeword.

[0054] Check codes include parity check codes, Hamming check codes, cyclic redundancy codes (CRC codes), and the like. The check code enables the encoding method to have certain error detection and even error correction capabilities. For the failure of looking up the status codeword in the code table, that is, in the case of abnormality, it is helpful to find out which part the problem lies in.

Embodiment 3

[0056] Based on the same inventive concept as the above method, this embodiment provides a PLC safety real-time monitoring and measurement system, such as figure 2 As shown, the system includes a real-time monitoring and measurement module, and the real-time monitoring and measurement module is connected with the CPU module, the input module and the output module of the PLC respectively;

[0057] In the preparatory stage, at first, by analyzing the application program of PLC, determine one or more operation key points in the operation process of the application program, and determine the PLC scanning cycle interval corresponding to the operation key point; the real-time monitoring and measurement When the module is in the normal running state of the PLC, according to the PLC scan cycle interval corresponding to the key point of operation, in each PLC scan cycle corresponding to the key point of operation, record the various inputs, outputs, and internal parameters of the PLC i...

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Abstract

The invention provides a PLC safety real-time monitoring and measuring method and system. According to the technical scheme, under various operation conditions of the normal operation state of the PLC, values of various inputs and outputs and various soft element states in the PLC are recorded and encoded when key points are operated, and a code table is formed; in the operation stage, values of various inputs and outputs and values of various soft element states in the PLC are collected and encoded at various operation key points, corresponding state code words are obtained, then the state code words are rapidly searched in a code table, if the state code words cannot be found, a PLC emergency response mechanism is started, and the safety of a PLC application system is protected. According to the technical scheme, the safety of the PLC application system can be continuously and rapidly measured when the PLC operates, PLC execution code exception and input and output exception can be found in time, and compared with the prior art, the higher safety protection requirement of the PLC application system can be met.

Description

technical field [0001] The invention relates to the field of industrial control and safety, in particular to a PLC safety real-time monitoring and measurement method and system. Background technique [0002] The industrial control system or industrial control system is an important part of the national industrial system and key infrastructure. The security of the industrial control system is related to the country's strategic security and social stability. [0003] Since the Iranian nuclear power plant was attacked by the "Stuxnet" virus, the industrial control system has gradually become an important target for attackers. Programmable logic controller (PLC) is an important basic control device in industrial control system, and its security issues have also received more and more attention. [0004] As industrial control systems move from closed to interconnected, a large number of PLC controllers are equipped with Ethernet communication components, allowing attackers to di...

Claims

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Application Information

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IPC IPC(8): G05B19/05
CPCG05B19/054G05B2219/1103
Inventor 张鲁国丁琦何骏廖正赟马骥江淋
Owner ZHENGZHOU XINDA JIEAN INFORMATION TECH
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